title: Analysis of HLA-DP in HLA-DR/GLO recombinant families and in the population of south-western France.
abstract: The existing estimates of the recombination fraction between DR and DP are quite variable and often based on anecdotal observations. We have estimated the DR/DP crossover frequency on the basis of families typed for HLA markers and GLO. The frequency of DR/GLO crossing over was 8.7% (23/264 informative meioses), maternal recombinations being about twice as frequent as paternal ones. Of 17 DR/GLO recombinant families typed for DPw1-6, DP was informative in 11 (13 recombinations) but only one of these gave rise to a DR/DP crossover. According to these data the DR/DP recombination fraction is below 1%, in contrast to some earlier published materials. HLA-DR/DP haplotypic associations on 127 informative Caucasoid haplotypes have been evaluated. In agreement with previous studies, DR3 was positively associated with DPw1 and, in addition, DR7 was found to be positively associated with DP-blank (not DPw1-6). The rare DPw6 allele is possibly associated with the DR4, Dw14 allele. The DR-DP haplotype profiles suggest other associations which might become significant if larger materials are tested. The frequency of DP alleles in a random material (N = 201) was found to be in accordance with most of the previously published frequences on European Caucasoids with DPw4 as the predominating frequency (gene frequency 40%) and a blank frequency of 27%.
authors.affiliation: INSERM U.100, Toulouse, France.
authors.forename: M
authors.initials: M
authors.lastname: Thomsen
authors.forename: S
authors.initials: S
authors.lastname: Essaket
authors.forename: A
authors.initials: A
authors.lastname: Cambon-Thomsen
authors.forename: F M
authors.initials: FM
authors.lastname: Robbins
authors.forename: R J
authors.initials: RJ
authors.lastname: Hartzman
authors.forename: J
authors.initials: J
authors.lastname: Arnaud
authors.forename: E
authors.initials: E
authors.lastname: Ohayon
mesh_terms: D000483:Alleles; D005602:France; D006682:HLA-DP Antigens / Q000235:genetics*; D006684:HLA-DR Antigens / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D007791:Lactoylglutathione Lyase / Q000235:genetics*; D011995:Recombination, Genetic
chemical_list: D006682:HLA-DP Antigens; D006684:HLA-DR Antigens; D007791:Lactoylglutathione Lyase